This method varies from a simple box shape to a Bartlett triangle to a decent-looking smooth blur as Quality is increased. It is a little better at preserving detail in less-blurred areas than Multibox.

Similar to Soften, this gives a better Gaussian approximation at higher Quality settings.

Not really a true defocus, this gives a flat, circular shape to blurred pixels that can approximate the look of a defocus.

Increasing Quality gives smoother blurs, at the expense of speed. Quality set to 1 uses a very fast but simple box blur, for all Method settings. A Quality of 2 is usually sufficient for low Blur Size values. 4 is generally good enough for most jobs unless Blur Size is particularly high.

This selects which channel of the Blur Image controls the amount of blurring applied to each pixel.

When selected ony a Blur Size control is shown and changes to the amount of blur are applied to both axes equally. If the checkbox is cleared, individual controls appear for both X and Y Blur Size.

Increasing this control will increase the overall amount of blur applied to each pixel. Those pixels where the Blur Image is black or non-existent will never be blurred, regardless of Blur Size.